What am I doing wrong? Rendering takes forever
FBX doesn't export simulations unless you are exporting every vert position in every frame and that is absolutely not optimal. I assume you are trying to export this to a game engine because FBX is 3d model format. If you are using a game engine you have two options:
Do the vfx in the game engine instead. Blender's vfx system cannot transfer into game engines.
Render out your animation and use the video in your game engine: and in the properties panel&lt;Scene&lt;Film&lt;Render click the check box next to Transparent background. I think the QT video codec supports transparent video. This method is not optimal.